TUI confirmed reports in German newspaper Das Bild that it was renegotiating contracts to protect it from a switch back to the drachma, whose value would likely drop sharply if it replaced the single currency.
A spokesman for TUI said the prospect of Greece returning to the drachma was “more than theoretical”.
The tour operator also said it was putting the interests of holidaymakers first in protecting itself against currency fluctuations.
The president of the Greek Tourism Association said hoteliers should not feel pressured into signing new contracts, which would allow TUI to pay them in “the new currency” as well as ensuring ongoing payments are received.
In its most recent quarterly results at the end of August, TUI Travel said the volume of its customers visiting Greece was up 11 per cent.